A 19-year-old woman is brought comatose after ingesting her mother's amitriptyline tablets. ECG shows sinus tachycardia with a QRS duration of 160 ms and blood pressure is 84/50 mmHg. The immediate specific treatment is:
- A Intravenous calcium gluconate
- B Intravenous sodium bicarbonate ✓
- C Intravenous amiodarone
- D Oral activated charcoal followed by flumazenil
Correct answer: B. Intravenous sodium bicarbonate
Explanation
Tricyclic antidepressant cardiotoxicity results from fast sodium channel blockade, producing QRS widening, hypotension, and arrhythmias. Sodium bicarbonate alkalinises the blood and raises extracellular sodium, displacing the drug from cardiac sodium channels. Amiodarone and other class III agents are avoided because they prolong repolarisation further. Calcium treats calcium channel blocker poisoning, not this entity.
Reference: Katzung Basic and Clinical Pharmacology, 15th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.